This invention relates generally to a miniature motor, and more particularly to a miniature motor having a positive temperature coefficient thermistor for preventing the miniature motor from being overheated by detecting motor temperature to control overcurrent, in which the positive temperature coefficient thermistor is fitted to an end face of the rotor core, or the positive-coefficient thermistor of a ring shape is fitted to the commutator disposed around the rotor windings to enhance the response of the positive temperature coefficient thermistor, improve the overheat preventing function of the miniature motor, reduce the size of the miniature motor, and improve productivity in the manufacture of the miniature motor.